package model;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class UserDao {
    //根据用户id进行查询
    public User selectUserById(int userId){
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;
        try {
            connection = DBUtil.getConnection();
            String sql = "select * from user where userId = ? ";
            statement = connection.prepareStatement(sql);
            statement.setInt(1,userId);
            resultSet = statement.executeQuery();
            if(resultSet.next()){
                User user = new User();
                user.setUserId(resultSet.getInt("userId"));
                user.setUsername(resultSet.getString("username"));
                user.setPassword(resultSet.getString("password"));
                return user;
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally{
            DBUtil.close(connection,statement,resultSet);
        }
        return null;

    }
    //根据用户名进行查询
    public  User selectUserByName(String username){
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;
        try {
            connection = DBUtil.getConnection();
            String sql = "select * from user where username = ? ";
            statement = connection.prepareStatement(sql);
            statement.setString(1,username);
            resultSet = statement.executeQuery();
            if(resultSet.next()){
                User user = new User();
                user.setUserId(resultSet.getInt("userId"));
                user.setUsername(resultSet.getString("username"));
                user.setPassword(resultSet.getString("password"));
                return user;
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally{
            DBUtil.close(connection,statement,resultSet);
        }
        return null;
    }
}
